39cc92ae7f
Text in command line flags referenced environment variables, moved that to subcommands to read correctly.
57 lines
1.4 KiB
Bash
57 lines
1.4 KiB
Bash
# To experiment with the command-line flags program it's
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# best to first compile it and then run the resulting
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# binary directly.
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$ go build command-line-flags.go
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# Try out the built program by first giving it values for
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# all flags.
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$ ./command-line-flags -word=opt -numb=7 -fork -svar=flag
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word: opt
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numb: 7
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fork: true
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svar: flag
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tail: []
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# Note that if you omit flags they automatically take
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# their default values.
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$ ./command-line-flags -word=opt
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word: opt
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numb: 42
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fork: false
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svar: bar
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tail: []
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# Trailing positional arguments can be provided after
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# any flags.
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$ ./command-line-flags -word=opt a1 a2 a3
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word: opt
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...
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tail: [a1 a2 a3]
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# Note that the `flag` package requires all flags to
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# appear before positional arguments (otherwise the flags
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# will be interpreted as positional arguments).
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$ ./command-line-flags -word=opt a1 a2 a3 -numb=7
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word: opt
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numb: 42
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fork: false
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svar: bar
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tail: [a1 a2 a3 -numb=7]
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# Use `-h` or `--help` flags to get automatically
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# generated help text for the command-line program.
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$ ./command-line-flags -h
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Usage of ./command-line-flags:
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-fork=false: a bool
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-numb=42: an int
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-svar="bar": a string var
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-word="foo": a string
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# If you provide a flag that wasn't specified to the
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# `flag` package, the program will print an error message
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# and show the help text again.
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$ ./command-line-flags -wat
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flag provided but not defined: -wat
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Usage of ./command-line-flags:
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...
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